1. Field of the Invention
The present invention relates to a machine tool for machining a workpiece with a relative displacement between the workpiece and a tool in three dimensional directions X, Y, and Z.
2. Description of the Related Art
In the field of machine tools, how to effectively remove or discharge a large amount of chips generated during machining is an important problem. Up to now, several companies have carried out research and development regarding this problem.
For examples, chip-removal structures are proposed, in Japanese Examined Patent Publication (Kokoku) No. 6-28835 and Japanese Unexamined Utility Model Publication (Kokai) No. 58-93437, wherein channels are provided on both sides of a table so that chips are separately received into the respective channel. In detail, the former publication discloses a chip-removal structure for a vertical type machining center wherein channels are provided on both sides of a table movable in X/Y directions so that chips are received by the respective channel and discharged outside therefrom by a chip-discharging means provided in the respective channel. The latter discloses a chip-removal structure for a horizontal type machining center wherein channels are provided on both sides of a table movable in Z direction so that chips are received by the respective channel and conveyed outside therefrom by a chip-discharging means by using a fluid provided in the respective channel.
However, according to the above prior art structures, there is a problem that the structure becomes complicated since the channels are separately provided in two locations and need two independent chip-discharging means respectively corresponding thereto. Also, the width of the channel in connection with the total width of the machining center is predetermined. In the prior arts, the channel is split into two separate channels, and the width of each separate channel is identical to one-half the predetermined width, thereby preventing a smooth flow of chips from a workpiece being machined. Consequently, a heap of chips (a nest-like pile of chips) is liable to form in the respective channels. This tendency would be enhanced, as the width of the machining center is reduced leading to a reduction in the width of the channels.